Effect of Clorhexidine-containing Adhesives on Early Dentin Shear Bond Strength

Zymographic studies have demonstrated successful inhibition of dentin matrix metalloproteinases (MMPs) collagenolytic activity with clorhexidine (CHX). Clinically, the use of topical 2%CHX prior to the application of the adhesive has shown good results. However, this represents an additional step in the bonding sequence.

Objective: To evaluate dentin shear bond strengths (SBS) of two recently developed adhesive systems containing 0.2%CHX at 24h, and to confirm the inhibitory properties of 0.2% and 2%CHX by gelatin zymography.

Methods: An etch-and-rinse and self-etch adhesives Peak Universal Bond (Ultradent), both containing 0.2%CHX, were evaluated. Each system was compared against a positive and a negative control (n=20). SBS was recorded after 24h of storage (100% humidity at 37°C). A one-way ANOVA was used for data analysis with a significance level of p<0.05. For zymographic analysis, extracts from concentrated demineralized human dentin powder were subjected to SDS-PAGE electrophoresis and incubated in the presence of CHX (0.2% and 2%). The gels were run in triplicate. Identification of MMP-2 and MMP-9 was confirmed by Western blot with specific antisera.

Results: No significant differences in SBS were detected among the tested groups (p=0.234). Zymographic analysis demonstrated inhibition of MMP-2 and MMP-9 irrespective of CHX concentration.

 

Group	Description	SBS MPa (SE)
1	35% H3PO4+Peak LC Bond Resin	40.1 (3.1)
2	35% H3PO4+Consepsis+Peak LC Bond Resin	40.8 (2.3)
3	35% H3PO4 +Peak Universal Bond	46.0 (1.6)
4	Peak SE Primer+Peak LC Bond Resin	39.9 (2.4)
5	Consepsis+Peak SE Primer+Peak LC Bond Resin	39.6 (2.5)
6	Peak SE Primer+Peak Universal Bond	37.3 (2.8)

Conclusions: Clorhexidine-containing adhesives yielded bond strengths similar to the control groups indicating that they may offer a simplified viable option for the application of the anti-microbial agent into the preparation. Inhibition of enzymatic activity was confirmed for both CHX concentrations.